Adenocarcinoma of the esophagus develops from metaplastic Barrett's columnar epithelia through the evolution of dysplastic epithelial intermediates. The role of dysplasia leading to adenocarcinoma is well established. Haggitt, R. C., Hum. Pathol. 25:982-993 (1994). A particularly strong relationship has been established between specialized intestinal-type Barrett's epithelium and adenocarcinoma (Haggitt, Hum. Pathol. 25:982-993 (1994); Hameeteman et al., Gastroenterology 96:1249-1256 (1989); Hamilton et al., Hum. Pathol. 19:942-948 (1988); Nishimaki et al., Cancer 68:1731-1736 (1991); Ovaska et al., Dig. Dis. Sci. 34:1336-1339 (1989); Reid et al., Gastroenterol. Clin. North Am. 20:817-834 (1991); Spechler et al., New Eng. J. Med. 315:362-371 (1986); Thompson et al., Hum. Pathol. 14:42-61 (1983)).
Gastroesophageal reflux disease is a common disorder affecting between 8 and 15% of the adult population in Western countries (Isolauri et al., Ann. Med. 27:67-70 (1995); Raiha et al., J. Am. Geriat. Soc. 40:1209-1211 (1992)). Columnar metaplasia of the esophagus, i.e. Barrett's esophagus, is reported in 8 to 24% of patients undergoing endoscopy for chronic symptomatic reflux (Haggitt, Hum. Pathol. 25:982-993 (1994); Ovaska et al., Dig. Dis. Sci. 34:1336-1339 (1989); Reid et al. Gastroenterol. Clin. North Am. 20:817-834 (1991); Spechler et al., New Eng. J. Med. 315:362-371 (1986)). Identification and follow-up of Barrett's esophagus is essential as these patients have a 30- to 40-fold increased risk of developing esophageal adenocarcinoma (Haggitt, Hum. Pathol. 25:982-993 (1994); Iftikhar et al., Gut 33:1155-1158 (1992); Reid et al., Gastroenterol. Clin. North Am. 20:817-834 (1991); Spechler et al., New Eng. J. Med. 315:362-371 (1986)).
Current management of Barrett's esophagus and specialized intestinal type Barrett's epithelium involves a program of endoscopic surveillance biopsies to detect dysplasia and early adenocarcinoma (Provenzale et al., Am. J. Gastroenterol. 89:670-680 (1994); Robertson et al., Br. J. Surg. 75:760-763 (1988)). High-grade dysplasia and early adenocarcinoma can be detected by endoscopic biopsy in patients without gross evidence of neoplasia (Levine et al., Gastroenterology 105:40-50 (1993); Reid et al., Gastroenterology 94:81-90 (1988)). While management of those patients with high-grade dysplasia remains controversial, the frequency of adenocarcinoma in the setting of advanced dysplasia (Haggitt, Hum. Pathol. 25:982-993 (1994); Miros et al., Gut 32:1441-1446 (1991); Starnes et al., Arch. Surg. 119:563-567 (1984)) has led to a recommendation for early resection.
Most authors agree that the development of adenocarcinoma in Barrett's esophagus, as well as other adenocarcinomas of the digestive tract, is preceded by a progression through increasing grades of dysplasia to carcinoma in situ and eventually to invasive cancer (Miros et al., Gut 32:1441-1446 (1991); Reid et al., Gastroenterology 102:1212-1219 (1992); Riddell et al. J. Pathol. 14:931-967 (1983)). These grades include non-dysplastic, low grade dysplasia, high grade dysplasia, carcinoma and eventually invasive cancer. Histological grading of dysplasia is subject to considerable variation among observers (Reid et al., Gastroenterology 93:1-11 (1987)). Consequently, many investigators have sought to characterize more objective changes in the dysplasia-adenocarcinoma sequence that would identify those patients with the greatest risk of developing cancer.
Recent studies suggest that mutations of the p53 tumor suppressor gene, as detected by immunohistochemistry or flow cytometry, may be predictive of progression to high-grade dysplasia and adenocarcinoma (Blount et al., Cancer Res. 51:5482-5486 (1991); Blount et al., Cancer Res. 54:2292-2295 (1994); Casson et al., Am. J. Surg. 167:52-57 (1994); Hardwick et al., Gut 35:764-768 (1994); Jones et al., Ann. Thorac. Surg. 57:598-603 (1994); Neshat et al., Gastroenterology 106:1589-1595 (1994); Sorsdahl et al., Cancer Detect. Prevent. 18:179-185 (1994); Younes et al., Gastroenterology 105:1637-1642 (1993)). Genetic instability, as determined by aneuploid or increased G2/tetraploid fractions in flow cytometric analysis, and cellular ultrastructural changes have been implicated in the development of adenocarcinoma (Levine et al., Gastroenterology 96:355-367 (1989); Meltzer et al., Cancer Res. 54:3379-3382 (1994); Reid et al., Gastroenterology 93:1-11 (1987); Reid et al., Gastroenterology 102:1212-1219 (1992)). Still, while the grading of high grade dysplasia has become more uniform, the reliable identification of low grade dysplasia versus readings of indeterminant or reactive changes remains problematic. Thus, no markers for low grade dysplasia have been identified. Furthermore, while a progression of dysplasia leading to adenocarcinoma is well accepted, little is known about the cellular changes occurring during the transition from Barrett's columnar epithelia to low grade dysplastic cells.
The grading of dysplastic cells in endoscopic biopsies remains the mainstay of prospective surveillance for patients with Barrett's esophagus. The frequency of endoscopic surveillance is strongly predicated on the determination of low or high grade dysplasia. The presence of high grade dysplasia or carcinoma in situ supports referral for early surgical resection. Evidence of low grade dysplasia has been suggested as an indication for greater vigilance in surveillance. Nevertheless, while grading of high grade dysplasia has relatively low interobserver variability, the grading of low grade dysplasia has been fraught with broad interobserver variability (Reid et al., Hum. Pathol. 19:166-178 (1988)).
The expression of a small GTP-binding protein, Rab11, has been recently described as an apically associated vesicle protein in a number of polarized epithelial tissues, including the gastric fundic, ileal, and colonic epithelia as well as the squamous epithelium of the esophagus (Goldenring et al., Am. J. Physiol. 270:G515-G525 (1996)). Rab11 was also expressed in a number of well-differentiated colonic adenocarcinoma cell lines (Goldenring et al., Am. J. Physiol. 270:G515-G525 (1996)). More recently, it has become apparent that Rab11 is a critical modulator of vesicle recycling to the plasma membrane (Calhoun et al., Yale J. Bio. Med. 69:1-8 (1996); Goldenring et al., Am. J. Physiol. 267:G187-G194 (1994); Green et al., Mol. Biol. Cell. 7:591 (1996); Ullrich et al., J. Cell Biol. 135:913-924 (1996); Urbe et al., FEBS Lett. 334:175-182 (1993)).
The evolution of adenocarcinoma appears to require a progression of cellular alterations through increasingly dysplastic lineages.
It is therefore an object of the present invention to provide a method and reagents to identify objective changes in the dysplasia-adenocarcinoma sequence that would identify patients with epithelium that have the greatest risk of developing cancer.
It is a further object of the present invention to provide methods and reagents for the reliable identification and grading of low grade dysplasia.